Davg <davidgrimsey <at> hotmail.com> writes: > I am trying to compare negative binomial models for the prediction of sports > games (I know that Poisson models would be better but I'm just trying > Negative Binomial at the moment). > > But, to compare the models I need them to have the same theta value. How > can I change the explanatory variables while maintaining the theta value?
library(MASS) modelfit <- glm(..., family=negative.binomial(theta=theta_value)) I believe that drop1() applied to a glm.nb() fit does this correctly (i.e. holds the theta parameter fixed at the estimate from the most complex model). ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
